On the role of modal intuition in modal logic

On Quantified Modal Logic

Propositional modal logic is a standard tool in many disciplines, but first-order modal logic is not. There are several reasons for this, including multiplicity of versions and inadequate syntax. In this paper we sketch a syntax and semantics for a natural, well-behaved version of first-order modal logic, and show it copes easily with several familiar difficulties. And we provide tableau proof ...

Modal Logic, Autumn 2007 FIrst Steps in Modal Logic

Modal logic is sometimes characterized as the logic of necessity and possibility, of “must be” and “may be”. The aim of this book is to present both semantical and syntactical features of the subject and to illustrate gy detailed analysis of the three most popular modal systems S5,S4 and K. The text presupposes some knowledge of classical logic, although the necessary information is briefly rec...

Modal Logic

Modal Logic in the Modal Sense of Modality

One reason is explained why the pursuit of modal logic’s original aim of evaluating the formal validity of arguments turning on necessity and possibility in a ‘metaphysical’ sense must cross borders and draw the logician into ‘metaphilosophy’. John P. Burgess Department of Philosophy Princeton University Princeton, NJ 08544-1006, USA [email protected]

The true modal logic

For Arthur Prior, the construction of a logic was a supremely philosophical task. As a logician, he could of course appreciate a finely crafted formal system for its own sake, independent of its " meaning " or philosophical significance. But a genuine logic-a good one, at least-lays bare the nature of those concepts that it purports to be a logic of: and this comes only by way of deep rellec-ti...